1. Field of the Invention
The present invention relates to a method for treating a surface of a rubber member suitable for a charge-imparting roller, a development roller, a cleaning roller, a toner-supply roller, a toner-regulating roller, an image-transfer roller, an intermediate image-transfer roller, a cleaning blade, a transfer belt, etc., for use in an image-forming apparatus such as an electrophotographic or toner-jet-type copying machine or printer. The invention also relates to apparatus for treating a surface of a rubber member (hereinafter may be referred to as surface treatment apparatus for a rubber member).
2. Background Art
Parts for use in an image-forming apparatus such as an electrophotographic or toner-jet-type copying machine or printer such as a charge-imparting roller, a development roller, a cleaning roller, a toner-supply roller, a toner-regulating roller, an image-transfer roller, an intermediate image-transfer roller, a cleaning blade, and a transfer belt are required to have a suitable conductivity, friction coefficient, and other physical properties and must not stain a contact member including a photoreceptor. Thus, hitherto, such parts made of polyurethane or silicone rubber have been provided with a surface coating layer in order to prevent staining of a contact member such as a photoreceptor and to attain suitable physical properties including charging property.
In recent years, the melting point of a toner binder for use in an electrophotographic copying machine has become lower and lower. In response to this trend, a development roller or a similar member is required to have low hardness so as to provide a sufficient deformation to ensure charging of the toner. Japanese Patent application Laid-Open (kokai) No. 2005-283913 discloses a development roller for satisfying the above requirement. The proposed roller, which includes an elastic layer, a urethane resin coating layer, and a thin layer formed of a hardened isocyanate, maintains softness over the entirety of the roller and has a hard surface.
Formation of a coating layer has a problem in that cumbersome steps are required, thereby increasing production cost. In an attempt to readily solve the problem, Japanese Patent application Laid-Open (kokai) No. 5-158341 discloses an approach including chemically treating a roller surface. Although the chemical treatment is an effective approach, a surface-treated conductive roller tends to have a hard surface. In practical use of a hardness-reduced roller, the surface of the roller is considerably deformed. Therefore, such a roller is required to have resilience in response to deformation. A roller having a hard surface-treated layer has insufficient resilience in response to deformation and may cause damage to an OPC or other members.